U.S. patent application number 13/807938 was filed with the patent office on 2013-05-02 for assembly and packaging method and system for optical components.
This patent application is currently assigned to OTX Ltd.. The applicant listed for this patent is Eli Benoliel. Invention is credited to Eli Benoliel.
Application Number | 20130108222 13/807938 |
Document ID | / |
Family ID | 44509511 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130108222 |
Kind Code |
A1 |
Benoliel; Eli |
May 2, 2013 |
ASSEMBLY AND PACKAGING METHOD AND SYSTEM FOR OPTICAL COMPONENTS
Abstract
A method of aligning an optical fiber with an optical component
in a micro-optical sub-assembly, comprises: providing a groove in
the micro-sub-assembly in alignment with the optical component; and
placing the optical fiber in the groove, thereby aligning the
optical fiber with the optical component. In this way a placement
tool with an accuracy of 50 microns can be used to place an optical
fiber with an alignment accuracy of one micron.
Inventors: |
Benoliel; Eli; (Or Akiva,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Benoliel; Eli |
Or Akiva |
|
IL |
|
|
Assignee: |
OTX Ltd.
Or Akiva
IL
|
Family ID: |
44509511 |
Appl. No.: |
13/807938 |
Filed: |
June 30, 2011 |
PCT Filed: |
June 30, 2011 |
PCT NO: |
PCT/IL2011/000522 |
371 Date: |
January 2, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61360541 |
Jul 1, 2010 |
|
|
|
Current U.S.
Class: |
385/83 ;
29/592.1; 29/832 |
Current CPC
Class: |
Y10T 29/49002 20150115;
G02B 6/36 20130101; H05K 13/04 20130101; Y10T 29/4913 20150115;
G02B 6/423 20130101 |
Class at
Publication: |
385/83 ; 29/832;
29/592.1 |
International
Class: |
G02B 6/36 20060101
G02B006/36; H05K 13/04 20060101 H05K013/04 |
Claims
1. A method of providing a micro-optical sub-assembly, comprising:
providing a groove in said micro-sub-assembly in alignment with
said optical component; and placing an optical fiber in said
groove, thereby aligning said optical fiber with said optical
component; placing said sub-assembly on a printed circuit board;
and extending said optical fiber into a ferule for onward
connection to external components.
2. The method of claim 1, wherein said groove is one member of the
group comprising: a v-shaped groove, a v-shaped groove having an
apex, the method comprising pressing said fiber firmly into said
apex, and a v-shaped groove cut into a length of silicon.
3-4. (canceled)
5. The method of claim 1, wherein said optical component is one
member of the group consisting of: a laser diode, a laser diode
having a wavelength which is at or below 365 nm, a photodetector,
and a laser diode combined with a photodetector.
6-8. (canceled)
9. The method of claim 3, wherein said groove and said optical
component are placed relative to each other such that said pressing
of said fiber firmly into said apex aligns said fiber with said
optical component to an accuracy of substantially one micron.
10. A method of providing a micro-optical sub-assembly, comprising:
placing an optical component on a holder, said holder configured to
distribute heat from said optical component; providing a groove in
a surface of said optical sub-assembly and an optical component
aligned therewith; and placing an optical fiber in said groove,
thereby aligning said optical fiber with said optical
component.
11. The method of claim 10, wherein said groove is a v-shaped
groove.
12. The method of claim 10, wherein said groove is a v-shaped
groove having an apex, the method comprising pressing said optical
fiber firmly into said apex.
13. The method of claim 10, comprising mounting said micro-optical
sub-assembly on a printed circuit board to form an optical
sub-assembly.
14. The method of claim 13, further comprising extending said
optical fiber into a ferule provided on said printed circuit board
for onward connection to external components.
15. The method of claim 10, I wherein said optical component is a
laser diode.
16. The method of claim 15, wherein said optical component has a
wavelength which is at or below 365 nm.
17. The method of claims 10, I wherein said optical component is a
photo-detector.
18. The method of claims 10, wherein said optical component is a
laser diode combined with a photo detector.
19. A micro-optical sub-assembly comprising: an optical component;
a holder for said optical component, said holder configured to
distribute heat from said optical component; a groove aligned with
said optical component; and an optical fiber aligned with said
optical component by placement in said groove.
20. The micro-optical sub-assembly of claim 19, wherein said groove
is a v-shaped groove.
21. The micro-optical sub-assembly of claim 19, wherein said groove
is a v-shaped groove having an apex and said optical fiber is
recessed into said apex.
22. A micro-optical sub-assembly comprising: an optical component;
a groove aligned with said optical component; and an optical fiber
aligned with said optical component by placement in said groove;
wherein said sub-assembly is placed on a printed circuit board,
said optical fiber extending into a ferule for onward connection to
external components.
23. The micro-optical sub-assembly of claim 19, wherein said
optical component is one member of the group comprising a laser
diode, a photo-detector and a laser diode together with a
photo-detector.
24. The micro-optical sub-assembly of claim 19, wherein said groove
is cut into a silicon base.
Description
FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention relates to an assembly or packaging
method and system for optical components and, more particularly,
but not exclusively to semiconductor lasers where accurate
alignment is required.
[0002] The accuracy with which component placing is required in the
field of semiconductor lasers depends on the wavelength of the
laser concerned. The shorter the wavelength the more accurately the
components need to be placed.
[0003] Short laser wavelengths are required for a variety of
applications. Thus lasers may be used for communications or to draw
structures on silicon wafers. For 1.5 .mu.m features, relatively
easy to handle laser light of 436 nm is sufficient. However as
features shrink below 1 .mu.m, diffraction around the mask edges
tends to lead to fuzzy lines and ineffective wafer components. This
problem can be solved by using shorter wavelength lasers but then
parts have to be more accurately aligned when constructing the
laser.
[0004] Likewise with communications, shorter wavelength lasers can
provide greater bandwidth.
[0005] Known techniques for constructing the laser components place
the components on the PCB, but have to use expensive specialist
machines for very accurate placing. The tools are expensive. The
general technique that is used is to place the laser on the PCB,
turn it on, find a maximum in the laser beam and then accurately
place an optical fiber at the beam maximum.
[0006] The present embodiments seek to address the above issue and
provide a simpler alternative for the placing of the fiber, given
the placement of the laser diode.
SUMMARY OF THE INVENTION
[0007] According to one aspect of the present invention there is
provided a method of aligning an optical fiber with an optical
component in a micro-optical sub-assembly, comprising:
[0008] providing a groove in the micro-sub-assembly in alignment
with the optical component; and
[0009] placing the optical fiber in the groove, thereby aligning
the optical fiber with the optical component.
[0010] In an embodiment, the groove is a v-shaped groove.
[0011] In an embodiment, the groove is a v-shaped groove having an
apex, the method comprising pressing the fiber firmly into the
apex.
[0012] In an embodiment, wherein the groove is a v-shaped groove
cut into a length of silicon.
[0013] In an embodiment, the optical component is a laser
diode.
[0014] In an embodiment, the optical component has a wavelength
which is at or below 365 nm.
[0015] In an embodiment, the optical component is a
photo-detector.
[0016] In an embodiment, the optical component is a laser diode
combined with a photo detector.
[0017] In an embodiment, the groove and the optical component are
placed relative to each other such that the pressing of the fiber
firmly into the apex aligns the fiber with the optical component to
an accuracy of substantially one micron.
[0018] According to a second aspect of the present invention there
is provided a method of providing a micro-optical sub-assembly,
comprising:
[0019] providing a groove in a surface of the optical sub-assembly
and an optical component aligned therewith; and
[0020] placing an optical fiber in the groove, thereby aligning the
optical fiber with the optical component.
[0021] In an embodiment, the groove is a v-shaped groove.
[0022] In an embodiment, the groove is a v-shaped groove having an
apex, the method comprising pressing the optical fiber firmly into
the apex.
[0023] The method may comprise mounting the micro-optical
sub-assembly on a printed circuit board to form an optical
sub-assembly.
[0024] The method may comprise extending the optical fiber into a
ferule provided on the printed circuit board for onward connection
to external components.
[0025] In an embodiment, the optical component is a laser
diode.
[0026] In an embodiment, the optical component has a wavelength
which is at or below 365 nm.
[0027] In an embodiment, the optical component is a
photo-detector.
[0028] In an embodiment, the optical component is a laser diode
combined with a photo detector.
[0029] According to a third aspect of the present invention there
is provided a micro-optical sub-assembly comprising:
[0030] an optical component;
[0031] a groove aligned with the optical component; and
[0032] an optical fiber aligned with the optical component by
placement in the groove.
[0033] In an embodiment, the groove is a v-shaped groove.
[0034] In an embodiment, the groove is a v-shaped groove having an
apex and the optical fiber is recessed into the apex.
[0035] An embodiment may be placed on a printed circuit board and
the optical fiber extending into a ferule for onward connection to
external components.
[0036] In an embodiment, the optical component is one member of the
group comprising a laser diode, a photo-detector and a laser diode
together with a photo-detector.
[0037] In an embodiment, the groove is cut into a silicon base.
[0038] Unless otherwise defined, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. The
materials, methods, and examples provided herein are illustrative
only and not intended to be limiting.
[0039] The word "exemplary" is used herein to mean "serving as an
example, instance or illustration". Any embodiment described as
"exemplary" is not necessarily to be construed as preferred or
advantageous over other embodiments and/or to exclude the
incorporation of features from other embodiments.
[0040] The word "optionally" is used herein to mean "is provided in
some embodiments and not provided in other embodiments". Any
particular embodiment of the invention may include a plurality of
"optional" features unless such features conflict.
[0041] Implementation of the method and/or system of embodiments of
the invention can involve performing or completing selected tasks
manually, automatically, or a combination thereof.
[0042] Moreover, according to actual instrumentation and equipment
of embodiments of the method and/or system of the invention,
several selected tasks could be implemented by hardware, by
software or by firmware or by a combination thereof using an
operating system.
[0043] For example, hardware for performing selected tasks
according to embodiments of the invention could be implemented as a
chip or a circuit. As software, selected tasks according to
embodiments of the invention could be implemented as a plurality of
software instructions being executed by a computer using any
suitable operating system. In an exemplary embodiment of the
invention, one or more tasks according to exemplary embodiments of
method and/or system as described herein are performed by a data
processor, such as a computing platform for executing a plurality
of instructions. Optionally, the data processor includes a volatile
memory for storing instructions and/or data and/or a non-volatile
storage, for example, a magnetic hard-disk and/or removable media,
for storing instructions and/or data. Optionally, a network
connection is provided as well. A display and/or a user input
device such as a keyboard or mouse are optionally provided as
well.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] The invention is herein described, by way of example only,
with reference to the accompanying drawings. With specific
reference now to the drawings in detail, it is stressed that the
particulars shown are by way of example and for purposes of
illustrative discussion of the preferred embodiments of the present
invention only, and are presented in order to provide what is
believed to be the most useful and readily understood description
of the principles and conceptual aspects of the invention. In this
regard, no attempt is made to show structural details of the
invention in more detail than is necessary for a fundamental
understanding of the invention, the description taken with the
drawings making apparent to those skilled in the art how the
several forms of the invention may be embodied in practice.
[0045] In the drawings:
[0046] FIG. 1 is a simplified schematic diagram illustrating a
micro-transmission optical sub-assembly (.mu.TOSA) according to the
present embodiments;
[0047] FIG. 2 shows a side view of the device of FIG. 1;
[0048] FIG. 3 is a side view of the photo-detector assembly of the
device of FIG. 1;
[0049] FIG. 4A is a simplified diagram illustrating an alignment
groove according to the present embodiments and shows an optical
fiber placed over the groove and inaccurately aligned;
[0050] FIG. 4B is a simplified diagram showing how the optical
fiber of FIG. 4A has fallen to the apex of the groove, thus being
accurately aligned;
[0051] FIG. 5 is a simplified diagram showing a variation of the
device of FIG. 1 in which the laser diode is provided but the
photo-detector is omitted;
[0052] FIG. 6 is a simplified diagram illustrating micro-receiving
optical sub-assembly (.mu.ROSA) according to the present
embodiments;
[0053] FIG. 7 is a side view of the embodiment of FIG. 6;
[0054] FIG. 8 is a simplified diagram illustrating a transmission
optical sub-assembly (TOSA) according to an embodiment of the
present invention incorporating the .mu.TOSA of FIG. 1 in a
PCB;
[0055] FIG. 9 is a simplified diagram showing a side view of the
packaged TOSA of FIG. 8;
[0056] FIG. 10 is a simplified diagram illustrating a receiver
optical sub-assembly (ROSA) according to an embodiment of the
present invention incorporating the .mu.ROSA of FIG. 6 in a
PCB;
[0057] FIG. 11 is a simplified diagram illustrating a side view of
the packaged ROSA of FIG. 10; and
[0058] FIG. 12 is a simplified flow chart illustrating an alignment
procedure for an optical fiber according to embodiments of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0059] The present embodiments comprise providing a laser diode,
photo-detector or other optical component, aligned with a groove.
Then the optical fiber is placed in the groove. The groove may be a
v-shaped groove having an apex and the fiber falls into the apex,
aligning itself with the optical component.
[0060] The required alignment accuracy is 1 micron. The prior art
provides a tool that precisely places the fiber to 1 micron
accuracy. The present embodiments may use a placement tool with an
accuracy of 50 microns since it merely needs to find the groove and
then the groove guides the fiber to the necessary accuracy of 1
micron.
[0061] Although accurate placement of the laser and alignment with
the groove are still required, this can be provided using
conventional equipment. The obviation of the need for accurate
placement of the fiber provides a considerable cost saving in terms
of the tools required.
[0062] The principles and operation of an apparatus and method
according to the present invention may be better understood with
reference to the drawings and accompanying description.
[0063] Before explaining at least one embodiment of the invention
in detail, it is to be understood that the invention is not limited
in its application to the details of construction and the
arrangement of the components set forth in the following
description or illustrated in the drawings. The invention is
capable of other embodiments or of being practiced or carried out
in various ways. Also, it is to be understood that the phraseology
and terminology employed herein is for the purpose of description
and should not be regarded as limiting.
[0064] Reference is now made to FIG. 1 which is an isometric
schematically illustrating a micro-transmission optical
sub-assembly (.mu.TOSA). The sub-assembly 10 comprises a silicon
fiber locator element 12 in which is etched a v-shaped groove. A
holder, 14, abuts the locator element. Mounted on the holder 14 is
laser diode 16. A space element 18 provides and defines a precise
separation space behind laser diode 16, and a further holder 20
abuts onto the space element 18. On the front of the further holder
20 a monitoring photo-detector 22 is mounted. Electrical contacts
24 are provided on the further holder 20. Wire bonding 26 connects
the optical components to contacts 24.
[0065] The holder 14 plays a part in distributing of heat from the
laser and may be mounted with a heat sink, as discussed in greater
detail below. Holes may be inserted in the holder for connection to
the heat sink.
[0066] FIG. 2 is a side view along the .mu.TOSA 10 of FIG. 1 The
parts are the same as those in FIG. 1 and are given the same
reference numerals.
[0067] FIG. 3 shows in greater detail the construction of the
photo-detector sub-assembly of FIG. 1. Again, the parts are the
same as those in FIG. 1 and are given the same reference
numerals.
[0068] Reference is now made to FIG. 4A which is a simplified
transverse cross section of the locator element 12, showing
v-shaped groove 40 etched therein. The groove 40 has apex 42
Optical fiber 44 is placed on the groove by an inaccurate placing
tool.
[0069] FIG. 4B shows how optical fiber 44 is brought into accurate
alignment by falling into apex 42 of the groove 40.
[0070] Reference is now made to FIG. 5 which shows a further
embodiment of a .mu.TOSA. The optical diode assembly of FIG. 3 may
be dispensed with to provide a three piece unit 50 comprising laser
16, groove locator 12 and laser holder 14.
[0071] Reference is now made to FIG. 6, which is a simplified
diagram illustrating a micro-receiving optical sub-assembly
(.mu.ROSA). Parts that are the same as shown in FIG. 1 are given
the same reference numerals and are not described again except as
necessary to describe the present embodiment. A receiving optical
sub-assembly simply detects incoming laser light and thus has a
photo-detector 22 in place of the laser diode. The photo-detector
22 is aligned with the groove which extends along holder 12 and is
spaced therefrom due to spacer 18, but otherwise the construction
is as described above.
[0072] FIG. 7 is a longitudinal side view of the .mu.ROSA of FIG.
6. The detail of the photodetector sub-assembly is as shown in FIG.
3.
[0073] Reference is now made to FIG. 8, which is a simplified
diagram of a transmission optical sub-assembly onto which the
.mu.TOSA of FIGS. 1-4B, or of FIG. 5 is inserted. PCB 80 has
connection pads 82 for electrical connections to external
equipment. A .mu.TOSA slot 84 accepts .mu.TOSA 86 and laser driver
88. Fiber 90 extends from ferule 92 and is aligned along the groove
so that it lines up with the laser inside the .mu.TOSA 86. Ferule
92 is placed in ferule slot 94 in the PCB 80.
[0074] Reference is now made to FIG. 9, which is a simplified
diagram illustrating the packaging of the optical sub-assembly of
FIG. 8. Parts that are the same are given the same reference
numerals. PCB 800 with .mu.TOSA 86 and laser driver 88 is covered
and sealed with cover 96. Heat sink 98, typically aluminium or
copper, is placed under PCB 80 to conduct heat away from the laser
diode and .mu.TOSA. Holes may be drilled in the PCB and the silicon
holders and may optionally be filled with metal to improve heat
conduction.
[0075] Reference is now made to FIG. 10, which shows the ROSA PCB
layout for the .mu.ROSA. Parts that are the same as in FIG. 8 are
given the same reference numerals and are not described again
except as necessary for an understanding of the present embodiment.
PCB 80 includes slot 100 into which is inserted TIA optical
receiver 102 and .mu.ROSA 104. Fiber 90 extending from ferule 92 is
aligned with the v-shaped groove as before.
[0076] FIG. 11 illustrates the cross-section of the packaged PCB of
FIG. 10. Parts that are the same as in previous figures are given
the same reference numerals and are not described again except as
needed for an understanding of the present embodiments. the figure
is in fact identical to that of FIG. 9 except that the TIA optical
detector and the .mu.ROSA replace the laser driver and .mu.TOSA
[0077] Reference is now made to FIG. 12, which is a simplified
diagram illustrating a method of aligning an optical fiber with an
optical component in a micro-optical sub-assembly. There is
initially provided a groove in the micro-sub-assembly in alignment
with the optical component. The optical fiber is then placed over
the groove and allowed to fall to the apex, thereby aligning the
optical fiber with the optical component.
[0078] The groove may be a v-shaped groove, and alignment may
involve pressing the fiber firmly into the apex. The groove may be
cut into a length of silicon, and the optical component may be a
laser diode or a photo-detector.
[0079] The laser diode may lase at a wavelength which is at or
below 365 nm.
[0080] It is appreciated that certain features of the invention,
which are, for clarity, described in the context of separate
embodiments, may also be provided in combination in a single
embodiment. Conversely, various features of the invention, which
are, for brevity, described in the context of a single embodiment,
may also be provided separately or in any suitable
subcombination.
[0081] Although the invention has been described in conjunction
with specific embodiments thereof, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, it is intended to embrace
all such alternatives, modifications and variations that fall
within the spirit and broad scope of the appended claims. All
publications, patents, and patent applications mentioned in this
specification are herein incorporated in their entirety by
reference into the specification, to the same extent as if each
individual publication, patent or patent application was
specifically and individually indicated to be incorporated herein
by reference. In addition, citation or identification of any
reference in this application shall not be construed as an
admission that such reference is available as prior art to the
present invention.
* * * * *